Phosphorescent fiber reinforced plastic article and process for making the same

ABSTRACT

A phosphorescent fiber reinforced plastic article comprising a fabric carrying a phosphorescent material encapsulated on a surface of a cured fiber reinforced plastic material made by a variety of processes including, but not limited to, pultrusion, compression molding, filament winding, contact molding, resin transfer molding, a continuous panel process, or structural reaction injection molding.

This is a division of U.S. patent application Ser. No. 07/618,966, filedNov. 28, 1990, now U.S. Pat. No. 5,135,591.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a phosphorescent fiber reinforced plastic(FRP) article and to a process for making such an article.

2. Description of the Related Art

Phosphorescent coated textiles and fabrics are known, as exemplified byU.S. Pat. No. 3,291,668 to Goldstein which teaches phosphorescentparticles on a textile substrate and then pressure laminating a clearplastic outer layer. The purpose of the invention is to provide animproved phosphorescent coated textile material, particularly for thefoot covering art.

U.S. Pat. No. 4,663,214 to Coburn teaches an improved phosphorescentmaterial decorative in visible light, and a process for making the same.The phosphorescent material comprises a support layer of opaquematerial, an intermediate layer of phosphorescent material incombination with an over layer of substantially iridescent material, anda top surface layer of protective material.

U.S Pat. No. 4,211,813 to Gravisse et al. teaches a photoluminescentflexible sheet material having an enhanced permeability to water vapor.The photoluminescent flexible sheet comprises a flexible substratehaving at least one coating film comprising at least one synthetic resinhaving dispersed therethrough a photoluminescent complex, said complexcomprising at least one phosphorescent metal sulphide and an organicsubstance which absorbs radiant energy and emits it in a wavelengthlying within the phosphorescent metal sulfide. The purpose of theinvention is to provide safety and protective garments.

U.S. Pat. No. 4,781,647 to Doave teaches extruding a thermoplasticpolymer containing a mixture of phosphorescent particles. The resultantfibers are then used to make doll hair which glows in the dark afterbeing submitted to a source of energy.

None of these patents teaches applying a phosphorescent material to asurface veil, fabric or mat and then using the resultant product toprovide a phosphorescent material on the surface of a molded articleformed from a fiber reinforced plastic material Incorporatingphosphorescent material technology into the fiber reinforced plasticmaterial manufacturing processes is not taught by the prior art.

The term fiber reinforced plastic (FRP) defines a material obtained by aseries of processes in which fibrous materials (glass, aramid, graphite,etc.) are combined with resinous materials, such as thermosetting orthermoplastic resins, to make a shape that is stronger than the resinitself. Thermosetting resins encompass a wide range of materialsincluding, but not limited to, polyesters, vinyl esters, bisphenol,epoxies, etc. A thermosetting resin is one which cures or polymerizesand cannot be melted and reshaped with the application of heat.

In fabricating a thermoset FRP part, typically the fiber reinforcementis saturated or wet-out with a liquid thermosetting resin. After beingwet-out, the saturated reinforcement is then shaped either manually ormechanically into the form of the finished article such as a part. Onceformed, the shape is then allowed to cure via the polymerization of thethermosetting resin. This is accomplished by a specific time andtemperature relationship based on the formulation of the resin.

Pultrusion is a thermoset FRP process wherein reinforcements andsurfacing fabrics such as mats or veils are drawn through a resin bathto achieve wet-out. Then they are pulled through a mold in the shape ofthe desired article. Typically, the mold is heated to accelerate thepolymerization.

Contact molding or open molding is another FRP process. Resins andreinforcements are manually (hand lay-up) or mechanically (spray-up)deposited on an open mold surface. The mold surface is preferablypreviously coated with a gel coat and is provided with a surfacingfabric such as a mat or veil. Once the required amounts ofreinforcements and resin have been deposited on the mold, the laminateis worked with rollers, brushes or squeegees, usually manually, toremove any trapped air and thoroughly saturate or wet-out thereinforcements with resin. Once this is completed, the laminate isallowed to cure, normally at ambient temperature.

Resin transfer molding (RTM) and structural reaction injection molding(S-RIM) are two similar closed mold FRP processes in which the requiredreinforcement package, including a surfacing fabric such as a mat orveil, is placed in one-half of the mold cavity, usually the bottom half.Once properly positioned, the top half of the mold is closed on thebottom half thereof and secured in place. Next, the resin is injectedslowly under minimal (e.g 50 psi) pressure in RTM or rapidly under highpressure (e.g. 2000 psi) in S-RIM. The mechanical pumping and resultingpressure causes the air to be flushed out of the mold cavity and theresin to saturate or wet-out the reinforcement. The resin impregnatedreinforced article is then allowed to cure.

Compression molding is also a FRP mold process. In this process, thereinforcement package including surfacing fabric (mats or veil) and theresin are placed on one-half, usually the bottom half, of the moldcavity. Once properly positioned, the top half of the mold ismechanically closed on the bottom half using a press which compressesthe reinforcement package and resin under pressure (from 50 to 1500 psi)to flush out the air and thoroughly saturate or wet-out thereinforcement package with resin. It is then cured normally with theassistance of heat.

Filament winding is a FRP process in which reinforcements, normallycontinuous rovings, are saturated with resin, normally by pulling themthrough a pan or bath containing the resin. The reinforcements are thenwound on a rotating mandrel in a specific pattern. The mandrel may ormay not have been previously covered with a resin impregnated surfacingfabric. An outer layer or outer layers of surfacing fabric may bewrapped over the resin impregnated reinforcement when required. Once therequired amount of resin, reinforcements and surfacing fabrics areproperly placed on the mandrel, the laminate is allowed to cure with orwithout the assistance of heat.

Continuous panel process is a FRP process for making continuous flatand/or shaped, e.g. corrugated, panels. It involves depositing a resinon a carrier film which then passes under a reinforcement depositionarea. Various types of reinforcement are then applied to the film ofresin. The reinforcement and resin then go through a compaction sectionwhere a series of belts, screens, or rollers force air out andthoroughly saturate or wet-out the reinforcement with resin. A surfacingfabric such as mat or veil is then placed on the surface of theresulting saturated material and the fabric is allowed to saturate withresin. A carrier film is then applied to the top surface of theresulting article which is passed through a curing station where theresin cures normally with the assistance of heat. Once cured, thecarrier film is removed and the article is cut to the desired length.

Previous attempts to add a phosphorescent material directly to a resinsystem have been unsuccessful, mainly due to the settling away of thephosphorescent material from the surface of the final article. This wasdue to the fact that phosphorescent materials have a relatively highdensity or specific gravity of e.g. 3.85-4.50, whereas the resin mixgenerally has a relatively low density or specific gravity of, e.g.,1.15-1.40. When put in the resin mix, the phosphorescent materials tendto sink to the bottom of the resin tank and/or wet-out pan. Little orless of the phosphorescent materials, therefore, become attached to thereinforcements or, more particularly, remain on the surface of themolded profile. Since the resin mixture is usually opaque due to theincorporation of fillers, any phosphorescent materials not on thesurface would tend to be shielded from exhibiting their afterglowproperties.

Putting the phosphorescent materials directly into the resin mix has notsolved the problem due to the overall opacity of the system. The resinmixtures usually contain ten to forty percent by weight of a filler.This causes the mix to be relatively opaque and prevents thephosphorescent materials from being charged by incoming light which, inturn, prevents the glow from being visible.

SUMMARY OF THE INVENTION

The present invention relates to a process for making a phosphorescentfiber reinforced plastic article comprising: (a) applying aphosphorescent material to a fabric; (b) combining fiber reinforcedplastic material whereby a portion of the resin in the fiber reinforcedplastic material forms a coating on said fabric; and (c) curing theresulting article.

The present invention also relates to a phosphorescent fiber reinforcedplastic article comprising a fabric carrying a phosphorescent materialencapsulated on a surface of a cured fiber reinforced plastic material.

The present invention overcomes the problems and disadvantages of theprior art by producing a fiber reinforced plastic article with aphosphorescent material on the surface thereof. This is accomplished byapplying a phosphorescent material to a fabric and then combining fiberreinforced plastic material with said fabric.

The present invention provides a fiber reinforced plastic article whichglows in the dark because the phosphorescent treated fabric remains onthe surface of the article, e.g. molded part. The phosphorescent fabricis encapsulated on a surface of the fiber reinforced plastic materialsince a portion of the resin in the material forms a coating on thefabric.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fabric is printed, coated, or treated with phosphorescent materials.The phosphorescent materials can be applied in the form of a paste,liquid dispersion, powder, or foam to the fabric.

Methods in which a phosphorescent material paste may be applied to thefabric are exemplified by, but not limited to, the following: (a)dipping then nipping, (b) screen printing (c) gravure roll printing, (d)froth or stabilized foam finishing application, (e) knife over roll, (f)knife over pad (g) knife over table, (h) conventional printing systemsfor textiles, (i) paint spraying unit, and (j) kiss rollapplicator/doctor blade. All of these methods are followed by curing thecarrier resin and drying.

Phosphorescent materials which can be applied to the fabric include, butare not limited to: zinc sulphide, calcium sulphide, strontium sulphide,cadmium sulphide, barium sulphide, magnesium sulphide aniline dyes andother coloring pigments or mixtures thereof. These materials possess a"glow in the dark" property when exposed to an energy source.

A fabric for use as the surfacing fabric is any non-woven, woven or matfabric which can be coated, finished and/or printed with phosphorescentmaterials. These include, but are not limited to, Nexus (a spunlacedpolyester fabric), Reemay (a spunbonded polyester fabric), Cerex (aspunbonded nylon), and various glass fabrics.

Nexus is a spunlaced polyester nonwoven fabric manufactured by PrecisionFabrics Group, Inc. One of its many uses is in the FRP industry where itis placed on the surface of a FRP article or part during the manufactureof the article. It provides improved appearance, corrosion resistance,weatherability and abrasion resistance by providing a resin richprotective surface to that article.

After the phosphorescent fabric is produced, it is applied to a fiberreinforcement resin by pultrusion, compression molding, filamentwinding, contact molding, resin transfer molding, structural reactioninjection molding or similar technique. The result is a FRP articlewhich glows in the dark because the phosphorescent treated fabric, e.g.mat or veil, is on the surface of the molded article, and isencapsulated in a thin resin layer.

These and other features and advantages of the present invention will bemade more apparent from the following examples.

EXAMPLE 1

A phosphorescent fabric was prepared as follows:

A phosphorescent coating paste was prepared with the components in TableI.

                  TABLE I                                                         ______________________________________                                                             BEFORE    AFTER                                                        SOLIDS CURING    CURING                                         ______________________________________                                        ROHM AND HAAS CAR-                                                                            45.5%    300 pts.  136.5 pts.                                 RIER TR 407 ACRYLIC                                                           LATEX                                                                         USR OPTONIX, INC. -                                                                           100.0%   104 pts.    104 pts.                                 PIGMENT #2330 -                                                               PHOSPHORESCENT                                                                ROHM AND HAAS   28.0%     5 pts.    1.4 pts.                                  THICKENER ASE60                                                               WATER           --        5 pts.      0 pts.                                  ROHM AND HAAS   30.0%     5 pts.    1.5 pts.                                  ACRYSOL RM-5                                                                  ASSOCIATIVE THICK-                                                            ENER                                                                          AMMONIA - AQUEOUS                                                                             --        3 pts.      0 pts.                                  26%                                                                           ______________________________________                                    

The above formulation of carrier resin, phosphorescent pigment,thickeners, water and ammonia was blended together to produce aphosphorescent coating paste with a viscosity of 22750cps (LVT. Spindle6;20 RPMS) with a pH of 9.6. Although the carrier resin in this Exampleis acrylic latex, it could also be selected from the group comprisingany epoxy, polyvinylchloride, ethylenevinylchloride, polyurethane,polyvinylacetate, acrylonitrile rubber, melamine and co-polymers ofthese compounds.

The phosphorescent paste was applied to a 1.3 ounce per square yardspunlaced (hydroentangled) polyester non-woven fabric (Sontara8010--DuPont) by knife over pad coating the paste to the surface of thefabric.

The paste was applied to the fabric at a temperature of 80° F. by scrapecoating with a beveled edge knife over a foam rubber pad to form asolid, uniform coating of 3.3 ounces per square yard. The coated fabricwas dried and cured in a forced air Mathis lab oven at a temperature of375° F. for thirty (30) seconds. The coated fabric displayed thefollowing properties:

                  TABLE II                                                        ______________________________________                                        PROPERTY  TEST METHOD       VALUES                                            ______________________________________                                        BASIS     ASTM D1117 517    4.3 oz./sq. yd.                                   WEIGHT                                                                        COLOR     N/A               Yellow-Green (on                                                              one side)                                         TENSILE   ASTM D1117 517    MD - 38.3                                         STRENGTH                    XD - 22.2                                         PHOSPHOR- Exposed to fluorescent                                                                          Bright Phosphor-                                  ESCENCE   cool white shade light box                                                                      escense (a light                                            for 15-minute duration;                                                                         yellow-green at                                             exposed to dark environ-                                                                        least for 30                                                ment where luminescence is                                                                      minutes)                                                    rated in a subjective                                                         manner.                                                             ______________________________________                                    

The phosphorescent fabric is suitable for application to a fiberreinforced plastic by means of pultrusion, compression molding, filamentwinding, contact molding, resin transfer molding, structural reactioninjection molding, a continuous panel process or other similar process.

EXAMPLE 2

A phosphorescent fabric was prepared by screen printing a sample ofNexus fabric with a phosphorescent material in the shape of a pattern,e.g. small hearts. The phosphorescent fabric was then incorporated intoa grating bar and pultruded. The resultant bar "glowed in the dark"because the phosphorescent materials were on the fabric and the fabricwas physically positioned on the surface of the bar and encapsulated bya micro thin layer of resin.

The pultruded bars exhibited the same unique phosphorescent propertiesof the printed fabric, indicating success in achieving phosphorescencein thermoset pultruded FRP parts.

Screen printing provides flexibility in determining the pattern andamount of surface that will be covered with the phosphorescentmaterials.

EXAMPLE 3

A phosphorescent fabric was prepared by printing with 100% coverage of aphosphorescent coating. The phosphorescent fabric was then slit intosample widths for experimental trials. Samples of pultruded grating barswere then run utilizing the phosphorescent coated fabric and athermosetting resin. The pultruded bars exhibited the same uniquephosphorescent properties of the coated fabric, indicating success inachieving a phosphorescent thermosetting pultruded FRP article.

EXAMPLE 4

A phosphorescent fabric was prepared by the same method as in Example 3.The phosphorescent fabric was combined to the fiber reinforced plasticwith an existing layer of fabric, which did not contain phosphorescentmaterials. Essentially, the part had two layers of fabric instead ofone. The lower layer, next to the resin, was free of phosphorescentmaterials while the upper layer was coated with the phosphorescentmaterials.

What is claimed is:
 1. A composite article comprising a combinedresin-containing fiber reinforced plastic and a fabric substrate havinga phosphorescent material distributed thereon wherein a portion of theresin from the fiber-reinforced plastic forms a coating over thephosphorescent material and the fabric.
 2. The article of claim 1, whichalso comprises a fabric free of phosphorescent material.